In the study, published online this week in the journal Current Biology, researchers at the Weizmann Institute positioned volunteers in a functional magnetic resonance imaging (fMRI) machine and presented them with a visual image along with a combination of pleasant and unpleasant smells and sounds.
A week later, the scientists repeated the process and found that the study participants remembered early associations more clearly when they were unpleasant, regardless of whether they were smelled or heard.
The authors point out that from an evolutionary standpoint it makes sense that the brain prioritizes unpleasant memories over pleasant ones. But they also noted that early smell memories are special.
Neurobiologist Yaara Yeshurun, the study's lead author, says, 'We found that the first pairing or association between an object and a smell had a distinct signature in the brain.'
The research could eventually help scientists boost memories, Yeshurun says, adding that 'Perhaps more importantly, it may help us generate methods to better forget early and powerful memories, such as trauma.'" (source)
